Process of making plaster board



March 3o 1926. 1,578,250

M. K. ARMSTRONG l PROCESS o MAKING PLASTER BOARD Original Filed Dec. 12,1921 2 Sheets-Sheet 1 March 30 1926. 1,578,250

M. K. ARMSTRONG PROCESS OF MAKING PLASTER BOARD Original Filed Dec. 12,`1921 2 Sheets-Sheet 2 Y. .NNY my my Patented Mar. 30, 1926.

\ UNITED STATES PATENT OFFICE.

MORGAN K. ARMSTRONG, OF HAMPTON, VIRGINIA.

PROCESS OF MAKING PLASTER B OARD.

To all whom 'it may concern:

Be it known that I, MORGAN K. ARM- STRONG, a citizen of the UnitedStates, and a resident of Hampton, in the county of Elizabeth City andbtate of Virginia, have invented certain new and useful Im rovements inProcesses of Making Plaster oard; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

This invention relates to an improved process for making plaster board,and consists of the matters hereinafter described and more particularlypointed out in the appended claims.

The object of the invention is to provide a novel and improved processfor the manufacture of plaster board of the kind described in anapplication executed of even date herewith, and comprising a plasterbody and to and bottom covering sheets of paper or ot er fibrousmaterial, vwith strips or bands of a nailing mixture forming the body atthe edges of the board and finishing the edges thereof. In order toillustrate my process, I accompany the application with drawings showinga machine or apparatus by means of which my improved process ma becarried out.

n the drawings Figure 1 is a diagrammatic view of a longitudinal sectionthrough the apparatus. igure 2 is a view representing a top plan view ofFig. 1.

Figure 3 is a view representing on an enlarged scale a transversesection throughv Figure 2 in a plane indicated by the line 3-3 of Figure2.

Figure 4 is a view representmg a horizontal section through Figure 3 ina plane indicated by the line 4-4 of Figure 3.

Figure 5 is a view representing on an enlarged scale a section throughFigure 1 1n the plane indicated by the line 5-5 lof F 1g. 1.

Figure 6 is a view representing a trans- 1 verse section through thefinished board.

My improved process is a contlnuous process and as to its generalfeatures is like the well-known continuous process by means of whichplaster board, comprlsing top and bottom covering sheets and anmterposed ,j Application filed December 12, 1921, Serial No. 521,577.Renewed July- 29, 1925.

ly spread over the advancing bottom sheet, y

and as it reaches the rollers13, 14 a top sheet 16, fed from a roll17over and about tension rollers 18,'and then about and under the toproller 13, is laid on and adhered to the layer,

of plaster. From the rollers 13, 14 the board thus made is fed over anendless conveyor belt 19, which is made of sufiicient length to permitthe setting of the plaster before the strip of board reaches the end ofsaid conveyor. The board is then cut to the desired lengths and is putinto kilns to dry.

In the present process, in addition to the layer of plaster material,there is laid on the advancing bottom sheet the bands or strips of' anailing mixture which is to form the edge of the board. This mixture maybe of any suitable composition, possessing the requisite properties of anailing miXture,- that is to say, a plastic mixture which, when dry, maybe Vpe-netrated by a nail withoutdisintegration yor cracking. Such amixture may be made from tar, sawdust or other fibrous material andclay, mixed while hot.

In carryingy out the process, and preferably, I make a board of doublethe intended width, which may be sawed or cut throu h the middle' toprovide two lengths of lie board. To this end,'in manufacturing theboard according to the process as carried outon the apparatusillustrated herein, I apply to the advancing bottom covering sheet 11,bands or strips of the plaster nailing mixture 20, 20 at the edges ofthe bottom sheet,

and an intermediate band of double width I 21 along the longitudinalmiddle line of the sheet. The strips or bands of the plastic nailingmixture are applied to the advancing bottom sheet in the positionsillustrated in- Figure 2 by any suitable means. As shown, I haveprovided hoppers 20, 20, and 21,

to which the soft plastic nailing mixture is mixture are driven in anysuitable manner (not shown) By this means and in this way the threebands of nailing mixture are laid on the advancing sheet, the surface ofthe sheet between said bands being left free and exposed.

The plaster to form the vmain body of the board, instead of beingapplied to the Whole width of the bottom sheet 1l, as heretofore, isapplied to the intermediate Widths or spaces 25,l 26 (see Fig. 2), beingdirected thereon from suit-able hoppers, not shown, by means of belts25, 2U, located at either side of the machine. The plaster is spreadover the sheet in the spaces 25, 26, intermediate the bands, to form themain body parts 25", 26" of the board and when the top sheet is appliedby the pressure of the roller 13 in the usual manner, said top sheet` isadhered not only to the main plaster body 25", 26" but also to thenailing mlxture bands 20, 21, 20. As the body with its covering sheetspasses between the rollers 13, 14, the plaster bodies 25", 26" areforced into intimate contact at their edges with the proximate edges ofthe several bands 20, 21, 20, of nailing mixture so as to provide anintimate union and bond between the two different characters of materialforming the body of the board.

In order to hold the said nailing mix bands in position and to preventthe plaster mix of the main body from being forced over the top of saidbands, I provide a pluraiity of mould plates 27, 27 and 28, 28, thefirst two named being directed along the inner edge of the outer nailing'mixture bands 20, 20, and the second two being located at either sideof the central nailing mixture band 21. These mould plates arepreferably made of glass and are supported in any convenient mannen-asforl example, by the bars 2 9, 29k which extend transversely of themachine and are' supported from the platform 12 by means of straps 30(see Fig.

3). The mould plates are mounted in brackets 31, each of which issecured to its bar 29 by means of a setscrew,--said bracket beingslidable on the bar so as to be capable of lateral adjustment thereon toadjust its position in accordance with the width of nailing mixture bandthat is to be applied. The front ends of said plates are curved asindicated at 32, to fit the bottom surface of the top roller 13, andhave ends or points 33 that terminate short of the vertical planethrough the axes of the rollers 13, 14. The mould plates are attached tothe brackets 31, as indicated, in such manner that they may 'be adjustedlongitudinally so as to bring the the mould plates prevent the plasterfrom coming into contact with the nailing mixture bands, said plates, aswill be understood, being adjusted to bear lightly on the top surface ofthe advancing bottom sheet. As the `points 33 ofy said mould platesterminate short of thevertical plane through the axes of the rollers 13,`14,-that is to say, short of the narrowest space separating they'sur.faces of said rolle1's,-just before the body is reduced to the finalintended thickness by passing between the rollers,vtlie plaster of thebody parts 25", 26" is forced laterally outward beyond said pointsagainst `the proximate edges of the nailing mixflliands 20, 21, 20, thusbringing about a forcing together of the several kinds of plasticmaterial composing thebody into intimate,l euga-gement at the point whenthe greatest pressure is exerted, with the result that a bond isafterwards formed between them when the plaster sets.

In order to smooth up and makelrne the outer edges of the two outermostnailing mixture bands 20, 20, it is preferable to provide a scraper orshoe 34, which is supported in such manner as to engage the edges of theadvancing board as the board passes through the vertical plane of thediameters of the rollers 13, 14. Said shoes as shown, are attached tothe straps which support the forward bar 29.

In order to provide a bevel at the edges of the hoard, one of therollers (as shown the top roller) is provided with a coniformcnlargement 13, and in the case where the board is made of double width,as illustrated herein, the same roll is 'provided with a coniformenlargement 13" at the middle,- the cones being oppositely disposed asshown in Figure 5.

After it is formed as above described, the board is carried over theendless conveyor 19, in the usual manner and allowed to dry or set,after which it is severed transversely into the desired lengths, andlongitudinallA f into the designed two Widths iof board, such as shownin Figure 6. The board isthen dried in suitable kilns in a familiarmanner. This completes the process.

The resulting board has true, straight edges which may be freely handledand l nailed in position without danger of marring or breaking the boardat or near said edges.

I claim as my invention:

1. The continuous pnocess ofl making plaster board, which consists ot'advancing a bottom covering sheet of fibrous material of the Width ofthe board to be made; of superimposing upon said sheet along its edges lribbons of a plastic nailing mixture, said ribbons being substantiallyrectangular in cross-section and of predetermined width and thickness;of spreading a plastic gypsum mixture over said sheet intermediate saidribbons; of confining said gypsum mixture to prevent its overflow onsaid ribbons while it is being spread; of superimposing a top coveringsheet of fibrous material of the same width as that of'the bottom sheeton said several plastic mixtures; and of applying pressure to the fullwidth of said top sheetto firmly adhere it to the top surface of thesaid several mixtures comprising the body of the board, at the same timeforcing the intermediate plastic mixture laterally outward at its edgesinto intimatevcontact with the proximate edges of said ribbons.

2. The continuous process of m-aking plaster board, which consists ofadvancing a bottom covering sheet of fibrous material of double thewidth of the board to be made; of superimposing upon said sheet alongits edges and along its median line ribbons of a plastic nailingmixture, said ribbons being substantially rectangular 1n cross-sectionand of predetermined Width and thickness and the ribbonl alon the medianline being double the width o the ribbons along the edges; of spreadinga plastic gypsum mixture over said sheet intermediate said ribbons; ofconfining said gypsum mixture to prevent its overflow on said ribbonswhile i-t is being spread; of superimposing a top covering` sheet offibrous material of the same width as the. width of said bottom sheet onsaid plastic mixtures; and of applying pressure to the full width ofsaid top sheet to firmly adhere it to the top surfacevof said severalplastic mixtures comprising the body of the board, and at the same timeforcing the plastic mixture intermediate said rib-- bons laterallyoutward at its edges intoA intimate contact with the edges of saidribbons.

3. The continuousv` pnoeess. of making plaster board, which consists ofadvancing a bottom covering sheet of fibrous material of the Width ofthe board to be made ;of superimposing uponsaid sheet along its edgesribbons of a plastic nailing mixture, said ribbons being substantiallylrectangular in cross-section and of predetermined Width and thickness;of spreading a plastic gypsum mixture over said sheet intermediate saidribobns'; of confining said gypsum mixture to prevent its overflow onsaid ribbons while it is being spread ;l of superimposing a top coveringsheet of fibrous material of thc same width as that of the bottom sheet-on said several plastic mixtures; of applying pressure to the fullwidth of said top sheet to firmly adhere it to the top surface of thesaid several mixtures'comprising the body vward at its' edges intointimate contact with the proximate edges of said ribbons; and of facingthe outer edges of said ribbons to form and smooth the edges of theboard;

4. The continuous process of making plasf ter board, which consists ofadvancing a bottom covering sheet of brous material of the width of theboard to be made; of superimposin upon said sheet in predetermined linesrib ons of a plastic mixture capable of being given a definite form incross-section when in a plastic state; of spreading a plastic mixture ofa different consistency over said sheet intermediate said ribbons; ofconfining said intermediate mixture to prevent its overfiow on saidribbons; of superimposing a top covering sheet of fibrous material ofthe same Width as said bottom sheet on saidseveral plastic mixtures; andof applying pressure to the full width of said top sheet to firmlyadhere it to the top surface of said several plastic mixtures comprisingthe body of the board, and at the same time forcing the intermediateplastic mixture laterally outward at its edges into intimate contactwith the proximate edges of said ribbons to join said several plasticmixtures into a single body for the board.

5. The continuous process of making plaster board, which consists ofadvancing a bottom covering sheet of fibrous material of the width oftheboard to be made; of. superim- .posing upon said ysheet along itsedges ribons of a plastic nailin mixture, said ribbons being.substantial y rectangular in cross-section and of predetermined widthand thickness; of spreading a plastic gypsum mixture over said sheetintermediate said ribbons; of superimposing a top covwidth as that ofthe bottom sheet`on said several plastic mixtures; and of applyingpressure to the full width of said top sheet Ito firmly adhere it to thetop surface of the said several mixtures comprising the erlng sheet offibrous'material of the same body of the board, at the same time,forcing the intermediatel plastic mixture laterally outward at itsedges into intimate contact with the proximate edges 0f said ribbons.

6. Thecontinuous rocessrof making plaster board, which consists ofadvancing a bottom .coverin sheet of fibrous material of double thewldth of theboard to be made; of superimposing upon said sheet along itsedges and along its median. line ribbons of a plastic nailing mixture,said ribbons being su stantially rectangular in cross-section and ofpredetermined width and thickness and the ribbon alon the median linebeing double the width o the ribbons along the edges; of spreading aplastic gypsum mixture over said sheet intermediate said ribbons; ofsuperimposing a top covering sheet ot fibrous material of the same Widthas the width of said bottom sheet on said plastic mixtures; and ofapplying pressure to the e full width of said top sheet to firmly adhere`outward at its edges into intimate contact with the edges of saidribbons. v

7. The continuo-us process of making plaster board which consists ofadvancing a bots tom covering sheet of fibrous material of the widthotthe board to be made; ot superimposing upon said sheet along its edgesribbons ot' a plastic nailing mixture, said ribbons being substantiallyrectangular in cross-section and otl predetermined width and thickness;of spreading a plastic gypsum mixture over said sheet intermediate saidribbons: of superiml'iosing a top covering sheet of fibrous material ofthe same width as that ot' the bottom sheet on said several plasticmixtures; of applying pressure to the full width o't said top sheet tofirmly adhere it to the top surface of the said several mixturescomprising the body of' f the board, at the same time forcing theintermediate plastic mixture laterally out- Ward at its edges intointimate contact With the proximate edges of said ribbons; and of facingthe outer edges of said ribbons to form and smoooth the edges of theboard.

8. The continuous process of making plaster board, which consists ofadvancing a bottom covering sheet of fibrous material of the width` ofthe board to be made; of superimposing upon said sheet in predeterminedyaol sheet on said several plastic mixtures; and

ot applying pressure to the full Width of said top sheet to firmlyadhere i-t to the top surface of said several plastic mixturescomprising the body of the board, and at the same time forcing theintermediate plastic mixture laterally outward at its edges intointimate Contact with the proximate edges of said ribbons to join saidseveral:.plastic mixtures into a single body for the board.

In testimony that I claim the :foregoing as my invention, I aix mysignature this 11th day of July, A. D. 1921. i

MORGAN K. ARMSTRONG. l

